Stuck in Low Power Mode

Mike Suffolk

Finding my (electric) wheels
Jun 21, 2024
7
0
Hi, I’ve had a pre owned Juicy Classic for three years (four year old bike). It’s in excellent condition and hardly done any miles. This June having checked and charged the bike after winter storage I took it out. All lights on but bike does not move out of low power, lights change but bikes motor does not. Never had any problems before. Any ideas?
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,797
3,133
Telford
OK, that could be analogue or digital.
Analogue ones need 4 wires. They need battery supply for power (normally red 36v and black ground). When switched on, they connect the battery voltage to a third wire, which goes back to the controller to power it (normally blue, sometimes pink or orange). The 4th wire is the one that determines the power level - something like 1v for level 1, 2v for level 2, 3v for level 3 and 4v for walk assist (normally green)

Digital ones need 5 wires. The first three are the same as above. Wires 4 and 5 transmit and receive data (marked Tx and Rx on any pcb and are typically yellow, green or white).

Whatever you have, the controller will give level 1 if the data comms don't work or there is no voltage on the green analogue wire, so the probability is that one of those wires has been pulled and is now disconnected.

Another potential cause is when water gets in the control panel and wipes out software or comms.

If it's a 4 wire one it's easy to test the green wire by either opening the motor controller or directly on the connector if it's the block type.

If the control panel has screws in the back, open it up to see if a wire is off or whether there's any water damage.

You can make an opportunity out of a crisis by upgrading your controller and control panel to KT ones for about £80, which will be a massive improvement to your bike's power control and ride quality, so don't waste money on replacement parts without considering that. The change normally requires some soldering of wires.
 

Mike Suffolk

Finding my (electric) wheels
Jun 21, 2024
7
0
Thanks for your help. Solution beyond me im afraid, no idea about electrics, hoping it might just need a replacement of something.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,797
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Telford
Thanks for your help. Solution beyond me im afraid, no idea about electrics, hoping it might just need a replacement of something.
You have to test to find what needs replacing, otherwise it can become very expensive. Don't you have a family member, friend or neighbour that knows how to use a screwdriver and a meter?
 

Bikes4two

Esteemed Pedelecer
Feb 21, 2020
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431
Havant
... This June having checked and charged the bike after winter storage I took it out. .....
Did you periodically charge the battery at all over winter? If not and the battery went flat and given it's 4 years old, then your battery may have been weakened such that is can deliver enough power for low levels of assist but when you ask for more power, the battery can't cope.

Again, these things are checkable if you have a volt meter plus some guidance from those on here on what to look out for.
 

Mike Suffolk

Finding my (electric) wheels
Jun 21, 2024
7
0
Did you periodically charge the battery at all over winter? If not and the battery went flat and given it's 4 years old, then your battery may have been weakened such that is can deliver enough power for low levels of assist but when you ask for more power, the battery can't cope.

Again, these things are checkable if you have a volt meter plus some guidance from those on here on what to look out for.
Yes, charged up occasionally over the winter
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
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Wiggle every connector you can find, if the battery is removable, take it out out, check pins, put it back....
 

Mike Suffolk

Finding my (electric) wheels
Jun 21, 2024
7
0
Wiggle every connector you can find, if the battery is removable, take it out out, check pins, put it back....
Done all that Matthew thanks. I’m taking it to a juicy repair guy next Tuesday, perhaps he can fix it. I was hoping someone had experienced this before on here and it was a common problem with an easy fix, alas no.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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West Sx RH
Fault is most likely within the display so a short of a kind , faulty wiring or moisture tracking between solder pads is the most likely .

Another thread quite similar was on the boards this week and the guy had no selection from his display , he opened it and supplied pics where it was instantly ascertained that his Gnd wire was broken.
 

Mike Suffolk

Finding my (electric) wheels
Jun 21, 2024
7
0
Fault is most likely within the display so a short of a kind , faulty wiring or moisture tracking between solder pads is the most likely .

Another thread quite similar was on the boards this week and the guy had no selection from his display , he opened it and supplied pics where it was instantly ascertained that his Gnd wire was broken.
Cheers Nealh